Plunger type electrical switch



I Aug. 17, 1943. R. HETHl-:RINGTON 2,326,942

PLUNGER TYPE ELECTRICAL SWITCH Filed Sept. 15, 1959 A Il; .fm

the annularcontat.

yom; 'swrrorr l 1 f kai mamas.

y' f Mgr/,present inrentionfrelatesltoa 'i j electric .switchojperatingytbrougna bell-ow switchv .'sliank.-

YA ,purpose yof",.theyfir'rvig-zrltion.g is to-,accumulate resilient vstartin-g .energy jfor a .push :bar type; switchfliavng anY impressed starting .resistance until the pressuresuddengly @Neroemes-vlineY im@ l ,Aiurther ,purpose y.ist to proa/fide"v struc-f.A

pressed ,starting for! ar quick. forward L v movementlofvtlielbar,

ture of thecharacter indicatelthatwilllstay,sate l Y' Y er underthe heavy dutyseruice vmeten'aircraft1an-d.v

Y I particularly' suited to easy am@ inexpensive nfiani'lf'acturel K l Afurther purpose'isto -resist hand;starting of Y1 a hand operateclllongtudinally mQ'Vable ,push bar typesvjitchsby yspring stops, preferably Contact @firing-Springs, @waging the baffi f A further purpose is tosecure a q' ck break ofY ofthe cire-u supreme ,Y t l strains diagonaltoV thel` lengtlifstof Vtlflesegrooves.

inl-The electricallyconductingY outer ends .of the a, resi-liently breaking pushvbar. cone-break type Sivitch. using' starting lbesiiudirial'mevemeut Gfthe bar .to concurrent@ v'start `lateral outward- 4movement; away from'theconev-of: contactslat' op-' posite sides of the oneand,longitudinal moi/ement of theeone awayiroi'rlifthecontaets. Y n Y A'ffurthelpurpose is to provide no'veland ine expensii/'ev structure for 'mounting anannular, preferably conical; contact in'y cooperative -relation wth circuiti ferent'ially`4 l spaced internally (zoned contacts o'ri'ning parts of anexternal cir-V yuitfrto make vandV breakeleot-ric connections be-v Yttifeeri the spacedvqontacts by longituriinal move-o` ments ofrtrheannular eontactiandgtoclean-.the env v .sagement surfacesbetween *the spacedl .contacts andr ythe annular contact by rotary movement of;

bestlicoperaition with anaririular' inner'. Contact Y 3 {5Z'g`lisli0wn as a cone, ,mounted upon the "plunger `assembly. Both' *tbe` outerfvrland innerV contacts a push bar or plungerf- 2Q v'projecting f shank.Y This bar. f Iterial. .l

provide@ with l l YtZE--suitablyA Bakelitel nally groot/*ed atZLlB to receivelelectricall'y con-"L 'Y ing' asse'rribly,-and,a plungerassembly;V

v 'Y The r'nain :housing assemblyfas shown co Y `I`8,,open at one end','; f 'with opposite-recesses.19 'Qf'zwhichone 'only :is

'shown to 'accommodate'thefterminal`rr1ount asf@ f Y sembly. At th'eother end it is reduced at shoufder 2l to an externallythreaded hollowztubular". shank `22' for use in supporting tlie Wholest'r" 'c. Y tur'efrom Ya switchboardjrfthe like, notfshow' y.

prises a' hollow metal casing The shank 22];supportstheoperating ndm n Y ghthe {plunger` is i of l insulating'ina- .An interrnediate due'tmg 'entaetf 'strips 21,1 f2s .which-rom 'Apart stripsiormcoptacts 3l landere in positionfor The bar 24 f the plunger assembly,"llure'l,

' may' form part'rofa composite plunger., -See Fig- Further Vpurposes# I will tion and in the claimsj I have elected to slfrw Vention thatv are pxraqtical and*k efficient inzoperf.

iwhichg Wellf illustrate, Jthe i principles yglvloifable contacts offd'ifferertinetalscan'd ,any

autres@ ure 2b for. Qnewaym 'which 'itjmay 15e/assemblea.

Intermediate the plunger, Valong areducedrsirv*latedportion of thepluugerl'are located the inner YContact and insulating Washersor collars tirantil Q34, engaging-and insulating fthe front land back of thecontact. l These collars, and. particularly ,collar 33rpay-beused to separate tlfiegoutercontavctsl Collar 35`isxed Iin positiong `.flreierably rmetaigitaliows the pmngertopass through it,

surrounds the reduced part 3650i the plunger and receives the thrustr ofjthe barfsurroundng 'spring-MJT? l Y I Y Theparts of .the barrier-plunger. are thfrea'led together-1i an@ shouldered,in` any suitable rnanner 'as lconyenience ofv rn'antifacture .and Aassemblage makedesirable, 'l

other engagement of `diie'rer't Y'metals(thank rigid fastenngsof such'partsto each :othervareaVoidf-A edf and rnetal parts are desirably.- made either of silverlorlo'f lstainless steel except forgthey spring connected assemblies, respectively, a I'riafin hops-i ing assembly, :a--terlfninalqnount and endllltiis-vr orton of` .casing ylgis iienitudn 1 f t f Y nism, will compressv spring 18.

th@xr Opposite end there is a recess within which the'head 38 and the plunger near the head are 'Y adapted to travel when theoperating-v end is i pushed to theV left. The annular inner contact V32,l most com/eniently of cone shape, is shown pinned at 42 to theA push rod. It tapers converging away-from the operating end ofthe push plunger in Figure 2 and toward the operating end inFigures 3, A4` and 5, Aand in retracted position of the push rod in most ofthe iigures engages the outer contacts 3|.'. yl

The outer contacts receive current throughU electrical binding posts 43 and 44;

lin'closedf position. In-Figure `A 2. (and also in Figures 3, 4 and 5) the spring contact 'strips are bent inwardly toform knees l9extending within the path of movement of an insulating collar 80 .pinned to thei plunger; Spring 3T presses against this .collar 80 and buildsup a considerable pressure before the knees snapvapart and the switch is opened quickly. s Theseparation of the knees spreads ,thev outer J contacts away Retraction of the innercon'tact takes place toward the right when Ypressure on the plunger is released. v

The terminal assembly as -illustratedincludesr.V

a block 48 of insulation materiaL;V suitably Bakelite, bored longitudinally (axially) to receive theVr plunger and is permissibly closed at the end, by a'plate 49. .v f

Each of the contactfstrips V21 and 28fto the 'rear ofthe sockets is upwardly turned and dished Vor grooved at 59 to provide spaced horns or prongs 60 which serve to Vseat between them and to prevent any sidewise turning ofthe out.- s`ide electricalconnectors fastened to the bindisposts, Y

Each contact-supporting strip v21er 28, com prises a thin strip' of spring copper or the like.

'Ihe outer contacts 3| are desirably concave on the faces toward the inner contact for best registry between the contact members.

rfrom the the the outer contacts.

ftion to be` engaged 4bythe outer contacts no matt knees" separated.'v

inner' Contact and movement of inner contact to the right to the end of its stroke carries it wholly beyond Itis then no longer in positer'howclose ,thespacing of these outer contacts; t The long outer surface of the collar 80 maintains the spacing by continuing to keep the ,1 Frequently; andit is believed more usually, such switches of normally closed type are hand operated.'A In those shown in Figures 3,4 and 5 the requisite hand pressure require'dto Vstart the switch'is stored, as it were, until the resistance presented by the' knees'Y of Figuresv 2, 3, 4 and 5 is overcome, when there isa sudden jump, with .first a full release :of the restraint.

`In Figures 3, 4` and 5 theknees 19 perform the double function of offering spring retardation to opening movementL to build vup pressure for a quick Yopeningand;A o f causing spreading,v of the outer'contactsf for quicker and surer spaoingcf 'The switch is Ysuitable fori normally closed cir- 'Y cuits, using switch forms suchlas those ,of Figures 3,4 andj 5. orV forno'rmally'open circuits,

using aswitch form such as that of Figure 2, ac'- l cording to the customers requirements.

The `cooperating edges of the [contacts and the proper collar (33 `in Figures 3,` 4 and 5) may be sloped to smooth out the cam action.

these contacts from the inner contact andreliably'maintainingthis space. 'Ihe collar `back Aofthe inner" contact is lengthenedf'asseen at 82, so as, lin plungerfmovementfrom right to left', to givearearwardly projecting edge 83' t0 engage,l accumulate pressure against,` rand finally at a jump V to spread the "knees andthe outer By sloping the ends Vof the outer contactsy as at 10, 10 and sloping the edges of thefcollars the outer contactfspacing from the inner contact may beincreased without danger of the collar"stubbing the ends of the outer contacts.

"I'hecollar and contact coneenter a recess suchV as 12. Y l In. aircraftV service the economy of space el- Y 33, 34, as at 1|, l'| l',outward wedging ofthe. contacts by the collars may be facilitated and fected by providing part of the stroke of the inner contact within the tubular Shankisimpirtant.

s WitCh.

When the switchis to be operatedtofclose the I5 threaded into the cap 11. The cap'is" pressed cutwardlyby a spring 18. The capfisifreejto telescope Vover1 the outerpart otthe plunger, at

thesame time"compressing the spring;` AH t'heV spring 18 be stiiferthanspring 31,pressure upon the cap tothe left will operate the plunger rst and, with further travel of the operatingniech'a- In 'Figure'2 a normallyopensswitch is shown It` lessens the requisitev length` vof contacts.

knees tends to tighten the outer contacts against the inner Contact." The long collar surface at 84 Vultimately nl 'aintains` the spacing of the knees.

The collars usedfY are rearwardly facing open cups in orderftorshorten the structure by permitting eachspring 31 to extend forwardly within its cup.

In the form shown i'n`Figure5 the abnormal closed ycircuit"positionoi the switch parts lies at Van lintermediate position in thethmw of the in-v ner contactr and the partsaer at open circuit at both extremities ofthe switchmovement. In

the normal position of Vthe' .switchgwith springY 31 expanded to: itsl fullextentthe washer 33 is wholly'within the recess and the inner contact lies part way within this reces The outery contactsv rest upon the extended coll 4 At the from; end the plunger ii's within '.12 and the insulated washer-33' rest against the i'langemslin Between thel plungerV end and the closed end'9 0 ofthe sleeve'lies a spring 93 The supplemental:spring is s tiil'er than .the

'l spring31.When the parts aremoved tothe left by pressure l'lponntheV end 90 lof the sleeve the spring 31 i-sjcompressedvtotli DOllt .where the plunger has completed travelwithin the switchl casi-ngfat which time; with further pre'ssurfe'the spring :839 "is'ccmpressed lto give" lost r motion movement o f the partsjV an insert servesthef'purpose or the'. sleeveIt is internally threaded. to Qreceive'an'[externally 75 V I threaded thimbie91,*c1osed-at'sz tofform a tery tent of*projeenen"desneezorftnez f, this thimbiegnetemnm mamme tardt n gaine/t the" upon the insulating operating sleeve.

Yation in thexstoppingjpoint vof Threading? the Vthinible :ip llinge :analisi-engaged b'yqoper' lock 'nutl again theV end Y 'l f siiown wnenstnepntsfarefa restpineswithsed 'yplunger@tremante-theleft.; when presse opening vr-nolvenfien4 f Si' Y. havin thus separate recess Tri-.nI Ythe-tnhiarf's templates; The knees ing "collar .lv in this ff te@ re e h t movement ,.OfY the Plunge in Athe""position fshoit/Tn Oasen-mu# l ndep" vthis crasemovement @f the; lunger t thefleftisf providedV` beforey the sieeveengage's the Contact strip knees, ytaking advantage of the inertia of from accidental engagement vvitnfthe-inner'oon- 'j right be 'permitted or provided for the recess Within'thev shank forms'a resting rpiacevjfor the collar 33 andthe outer contacts come tof rest Ultimatev tact. If full movementl of the plunger to the movement ofV the Contact sleeve -to'the left introduoes 10st motion, Y

the n operating permitting a oonsiderablevaristripsljmay lbei'nsedreithentoA ieinret wenn@ phi gerg'a casing'ierfthefrsnfiteh l n A, e thillilrig'erfaa utecfoniatsfwithin i the;r` pathgof* iInot/erneut oi'ljgtiief inner contant, adapted tofbengagledfvvithjmovementof the; plunger;fspringl supporting rstrips for the 4guter eon'taets,, 'insulationbetvveen thefspring supportf A; ingj stripsand theea'sing, inwardly, directedy knees oar `the' minngerrcomes omargifintm --iVYIltzWil befeviden.thatV h kneesoj Having 'tnusdesribe' ent '1,1

linger?feedV4 Q Pringy? eiff'contactsv `v having inwardly-extending `portiorie hief-mediate ithiileneths" fdf .engagement by.

" fisillation betWenihenriggSup# Y a'ndtheeasing', ndcarn means in@ nd asov in :the rearo-ffthe inner Contact 'portions of' their supports to in the entaot "strips, "insulating means4 carried by ing strips and thefcasinginwardly directed knees in the vcontact strips; insulating Vmeans', carriedfby therplunge'r engaging the knees to separate them vementr 'ff the inner com.

ppertings for thefoiitf "inner Contact l latingkmeans carried "by the plunger andatone limit of the plunger stroke adapted alsozto separate the outer contactsfgA ,Y s 4. A switch having a spring1opposed'operating carried by the plunger and outer contacts within the path 4of movement of the inner-contacthav` l'tooifer' .spring retardation torgtheiplungerymove f ment with subsequente'junipingof 'theplunger` and separationV of the outer contacts and insu- 'zbefenggdgby the; insulation ,ana-.messing fby whichthe'oute'r contact ngers are supported and l from `which they areinsulated..-..-, i

- 81AsWitchAcaSing,insulation within-'the casing,.spring iingers carried-by the: insulationand d having-inwardly-directedfcam knees, outer con- K plunger, Va casing for theswitc'li; aninner contact Y ing inwardly extending portions adapted. tobe" j engaged withmovement of :theplungenlspring supporting strips for theouter contacts, insulattion between the spring supporting strips-and the casing, and cam meanscarried by theplung'erlin front of and also in thefrearof the innerv contact engaging.- respectivelyl v the outer contactsv and their supports to wedgethe contactsfapart dur.'-

ing movement oi the plungerand to hold them in separated position. Y f

v 5. A switch having a spring opposed Voperating plunger, a casing for .the switch, an inner ta; pered contactcarried bythe plunger and outer contacts within thel path of movement ofthe in ner contact adapted to be Aengaged with move;Y

ment of the plunger, spring supporting stripsfor the outer contacts, insulationbetween `the spring supporting stripsandthejcasing, :arhollow tubular shank for attachment of. the switch, interiorly recessed to-receive-:the forward endoitheinnery contact andan insulating washer `carried by the plunger adjacentthe smaller 'end of the contact and of larger diairie'terv than vthatk of thevvsaid smaller end,v normallygresting within the shankandadapted toY engagegtheoutencontacts and hold `them apart.

Ytacts carried bythe lingers in frontV ofthe knees and sloping with Vrespect -toeach other, a plunger, 'ajztapered-nner contact :having av slope corre` sponding to theslopes :of `the outer contacts, an

"f insulating thimble, carriedby the plunger, andV a spring. havingoneendf'engaging theY inside of the thimble, opposing movementtofthe plunger and f permitting thespringftobe compressed, and the thimble -brought into engagement with the knees. n

. 9v.- In'a switch, a casing, "a 'longitudinally movable plungerguidedtherein, insulation within the casing, outer contact iingerses'upported from the insulation, outer contacts carried bythe fingers and sloping with respecttov each other, and an inner contact carried by the plunger and tapered Y Y forwardly and inwardlyto correspond with the :slope off thev outery contacts, inwardly vdirected knees inthe outerwcontact -fingers,..1insulation 6. In a switch, a ingitidmuy irivabie joprating plunger, a, spring surrounding the plunger and opposing vits movement, an inner contact carried by the plunger, outer contacts within the path vofV movement'of ,theA innerl contact vand adapted to be Vengaged by itgwith movement ofV the plunger, spring supportingA strips for the outer contacts, a c'asing,-insulation between the spring supporting strips and the` casing, inwardly `dif Vre'cted cam kneescarried by the supporting'sti'ips'V and insulating means surrounding one end of the spring andvsurrounding the plunger, carried by the plunger, and engaging withthecam knees to wedgethe outer contactsapart land out of enn gagement with thev innencontact and :holdrthem apart.

, F.Jln a plunger switch, a longitudiallymovable operatingvplunger, a springsurrounding the plunger, insulationsurrounding one endof the spring, an inner contact surrounding theplunger in front of the insulation,vr the contact'being tapered forwardly andinwardly, apair .of outer contacts fitting the taper. ofntheinner contact, spring fingers supporting therouter contacts and having inwardly directed cam knees `adapted to Y providing cam meansseparating the outer confcarried .bythe plunger at the rear of the inner contact adapted to engage 'the knees, and' insulation carried bythe plunger-in front of the inner contact and of larger diameter than the front end ,of the innerfcontachadapted tohold the oute contacts spaced from the inner contact.A .v

10, A .switch lhaving a longitudinally movable J plunger, a `spring surrounding the plunger and opposing its jmovement, an inner contact'A carried `by the plunger, outer contacts engaging the rst contact, insulationcarried by the plunger, springs tactsvwith movements of the plunger, and a casing about the plunger supportingfthe outer contacts through the springs.l v c Y ,11. A switch havinga spring-opposed-longitu- :dinally movable operatingplunger, a casing for vthe switch, an inner contact carried Aby the plunger, outer contacts engaging the inner contact, springs supportedV by the casing, carrying the outer contacts and themselves within the pathof movement of the inner contact,fadapted to be y' engaged with movement of the plunger, cams lo- 60 movement of the switch.

cated Within` the spring, and separate insulating means, one normally in Vfront and another nor- .mally behindthe outer contacts. inv direction of 1plunger movement, movable with'the inner contact and respectively holding the outer contacts apart and engaging the spring supported cams vto separate,` the outer contacts at one limit of ROBERT HETHERINGTON. s 

